import { Shader } from "../Shader";
const renderer = cc.renderer.renderEngine.renderer;

export class RainShader extends Shader {

    public name = 'RainShader';

    public params = [
        { name: 'texSize', type: renderer.PARAM_FLOAT2 },
        { name: 'resolution', type: renderer.PARAM_FLOAT3 },
        { name: 'time', type: renderer.PARAM_FLOAT },
    ];

    public defines = [
        { name: 'HAS_HEART', value: false },
        { name: 'USE_POST_PROCESSING', value: true },
    ];

    public frag = `
    // Heartfelt - by Martijn Steinrucken aka BigWings - 2017
    // countfrolic@gmail.com
    // License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
    
    // I revisited the rain effect I did for another shader. This one is better in multiple ways:
    // 1. The glass gets foggy.
    // 2. Drops cut trails in the fog on the glass.
    // 3. The amount of rain is adjustable (with Mouse.y)
    
    // To have full control over the rain, uncomment the HAS_HEART define 
    
    // A video of the effect can be found here:
    // https://www.youtube.com/watch?v=uiF5Tlw22PI&feature=youtu.be
    
    // Music - Alone In The Dark - Vadim Kiselev
    // https://soundcloud.com/ahmed-gado-1/sad-piano-alone-in-the-dark
    // Rain sounds:
    // https://soundcloud.com/elirtmusic/sleeping-sound-rain-and-thunder-1-hours
    
    #define S(a, b, t) smoothstep(a, b, t)
    //#define CHEAP_NORMALS
    
    uniform sampler2D texture;
    uniform vec4 color;
    uniform vec3 resolution;
    uniform float time;
    uniform vec2 texSize;
    varying vec2 uv0;
    
    vec3 N13(float p) {
        //  from DAVE HOSKINS
       vec3 p3 = fract(vec3(p) * vec3(.1031,.11369,.13787));
       p3 += dot(p3, p3.yzx + 19.19);
       return fract(vec3((p3.x + p3.y)*p3.z, (p3.x+p3.z)*p3.y, (p3.y+p3.z)*p3.x));
    }
    
    vec4 N14(float t) {
        return fract(sin(t*vec4(123., 1024., 1456., 264.))*vec4(6547., 345., 8799., 1564.));
    }
    float N(float t) {
        return fract(sin(t*12345.564)*7658.76);
    }
    
    float Saw(float b, float t) {
        return S(0., b, t)*S(1., b, t);
    }
    
    vec2 DropLayer2(vec2 uv, float t) {
        vec2 UV = uv;
        
        uv.y += t*0.75;
        vec2 a = vec2(6., 1.);
        vec2 grid = a*2.;
        vec2 id = floor(uv*grid);
        
        float colShift = N(id.x); 
        uv.y += colShift;
        
        id = floor(uv*grid);
        vec3 n = N13(id.x*35.2+id.y*2376.1);
        vec2 st = fract(uv*grid)-vec2(.5, 0);
        
        float x = n.x-.5;
        
        float y = UV.y*20.;
        float wiggle = sin(y+sin(y));
        x += wiggle*(.5-abs(x))*(n.z-.5);
        x *= .7;
        float ti = fract(t+n.z);
        y = (Saw(.85, ti)-.5)*.9+.5;
        vec2 p = vec2(x, y);
        
        float d = length((st-p)*a.yx);
        
        float mainDrop = S(.4, .0, d);
        
        float r = sqrt(S(1., y, st.y));
        float cd = abs(st.x-x);
        float trail = S(.23*r, .15*r*r, cd);
        float trailFront = S(-.02, .02, st.y-y);
        trail *= trailFront*r*r;
        
        y = UV.y;
        float trail2 = S(.2*r, .0, cd);
        float droplets = max(0., (sin(y*(1.-y)*120.)-st.y))*trail2*trailFront*n.z;
        y = fract(y*10.)+(st.y-.5);
        float dd = length(st-vec2(x, y));
        droplets = S(.3, 0., dd);
        float m = mainDrop+droplets*r*trailFront;
        
        //m += st.x>a.y*.45 || st.y>a.x*.165 ? 1.2 : 0.;
        return vec2(m, trail);
    }
    
    float StaticDrops(vec2 uv, float t) {
        uv *= 40.;
        
        vec2 id = floor(uv);
        uv = fract(uv)-.5;
        vec3 n = N13(id.x*107.45+id.y*3543.654);
        vec2 p = (n.xy-.5)*.7;
        float d = length(uv-p);
        
        float fade = Saw(.025, fract(t+n.z));
        float c = S(.3, 0., d)*fract(n.z*10.)*fade;
        return c;
    }
    
    vec2 Drops(vec2 uv, float t, float l0, float l1, float l2) {
        float s = StaticDrops(uv, t)*l0; 
        vec2 m1 = DropLayer2(uv, t)*l1;
        vec2 m2 = DropLayer2(uv*1.85, t)*l2;
        
        float c = s+m1.x+m2.x;
        c = S(.3, 1., c);
        
        return vec2(c, max(m1.y*l0, m2.y*l1));
    }
    
    void main()
    {
        vec4 iMouse = vec4(0.0, 0.0, 0.0, 0.0);
        vec2 fragCoord = vec2(uv0.x * texSize.x - 0.5 * texSize.x, 0.5 * texSize.y - uv0.y * texSize.y);
    
        vec2 uv = fragCoord.xy / resolution.y;
        vec2 UV = (fragCoord.xy+.5*resolution.xy) / resolution.xy;
        vec3 M = iMouse.xyz/resolution.xyz;
        float T = time+M.x*2.;
        
        #ifdef HAS_HEART
            T = mod(time, 102.);
            T = mix(T, M.x*102., M.z>0.?1.:0.);
        #endif
        
        float t = T*.2;
        
        float rainAmount = iMouse.z>0. ? M.y : sin(T*.05)*.3+.7;
        
        float maxBlur = mix(3., 6., rainAmount);
        float minBlur = 2.;
        
        float story = 0.;
        float heart = 0.;
        
        #ifdef HAS_HEART
            story = S(0., 70., T);
            
            t = min(1., T/70.);						// remap drop time so it goes slower when it freezes
            t = 1.-t;
            t = (1.-t*t)*70.;
            
            float zoom= mix(.3, 1.2, story);		// slowly zoom out
            uv *=zoom;
            minBlur = 4.+S(.5, 1., story)*3.;		// more opaque glass towards the end
            maxBlur = 6.+S(.5, 1., story)*1.5;
            
            vec2 hv = uv-vec2(.0, -.1);				// build heart
            hv.x *= .5;
            float s = S(110., 70., T);				// heart gets smaller and fades towards the end
            hv.y-=sqrt(abs(hv.x))*.5*s;
            heart = length(hv);
            heart = S(.4*s, .2*s, heart)*s;
            rainAmount = heart;						// the rain is where the heart is
            
            maxBlur-=heart;							// inside the heart slighly less foggy
            uv *= 1.5;								// zoom out a bit more
            t *= .25;
        #else
            float zoom = -cos(T*.2);
            uv *= .7+zoom*.3;
        #endif
        UV = (UV-.5)*(.9+zoom*.1)+.5;
        
        float staticDrops = S(-.5, 1., rainAmount)*2.;
        float layer1 = S(.25, .75, rainAmount);
        float layer2 = S(.0, .5, rainAmount);
        
        vec2 c = Drops(uv, t, staticDrops, layer1, layer2);
        #ifdef CHEAP_NORMALS
            vec2 n = vec2(dFdx(c.x), dFdy(c.x));// cheap normals (3x cheaper, but 2 times shittier ;))
        #else
            vec2 e = vec2(.001, 0.);
            float cx = Drops(uv+e, t, staticDrops, layer1, layer2).x;
            float cy = Drops(uv+e.yx, t, staticDrops, layer1, layer2).x;
            vec2 n = vec2(cx-c.x, cy-c.x);		// expensive normals
        #endif
    
        #ifdef HAS_HEART
            n *= 1.-S(60., 85., T);
            c.y *= 1.-S(80., 100., T)*.8;
        #endif
    
        float focus = mix(maxBlur-c.y, minBlur, S(.1, .2, c.x));
        vec3 col = texture2D(texture, UV+n).rgb;
                                // make time sync with first lightnoing
    
        #ifdef USE_POST_PROCESSING
            t = (T+3.)*.5;			
            float colFade = sin(t*.2)*.5+.5+story;
            col *= mix(vec3(1.), vec3(.8, .9, 1.3), colFade);	// subtle color shift
            float fade = S(0., 10., T);							// fade in at the start
            float lightning = sin(t*sin(t*10.));				// lighting flicker
            lightning *= pow(max(0., sin(t+sin(t))), 10.);		// lightning flash
            col *= 1.+lightning*fade*mix(1., .1, story*story);	// composite lightning
            col *= 1.-dot(UV-=.5, UV);							// vignette
    
            #ifdef HAS_HEART
                col = mix(pow(col, vec3(1.2)), col, heart);
                fade *= S(102., 97., T);
            #endif
    
            col *= fade;										// composite start and end fade
        #endif
    
        //col = vec3(heart);
        gl_FragColor = vec4(col, 1.);
    }`;

};